No error description when a required field in referenced entity is not filled

Problem/Motivation

When a required field of the referenced entity is not filled, while adding another referenced entity, the field is highlighted with red error border as expected. But there is no error text saying that the field is required. This happens only when the reference field is multi-valued and "Inline entity form - Simple" widget is used.

Steps to reproduce the issue

1. Create two content types: "Article" and "Basic Page".
2. Make "Body" field of "Basic Page" content type required.
3. In "Article" content type, add a new Reference field pointing to "Content". Name it as "IEF". Make this a multi-valued field.
4. On /admin/structure/types/manage/article/fields/node.article.field_ief, in "Reference Type" fieldset, choose "Basic page" as content type and save.
   
5. Go to "Manage Form Display" of "Article" content type (/admin/structure/types/manage/article/form-display). Make the widget of "IEF" field to be "Inline entity form - Simple".
   
6. Go to "Create Article" form page (/node/add/article).
7. Fill title of the article as "Test article".
8. Fill title of the page referenced in IEF field as "Test page". Keep "Body" field empty.
9. Click on "Add another item" below.
10. You will see a red border around the "Body" field inside the IEF fieldset. This is expected since the "Body" field is required but is not filled.
11. But there is no error text mentioning that the "Body" field is required.